Tricuspid Atresia

Heart With Tricuspid Atresia

Atresia is defined as the congenital absence of a normal opening. In the case of tricuspid atresia, the tricuspid valve is not present resulting in a lack of communication between the right atrium and the right ventricle. Consequently, the right ventricle is small and underdeveloped. An associated ASD allows blood to be diverted from the right to the left atrium. Survival depends on the presence of a VSD or on the ductus arteriosus remaining open after birth in order for blood to reach the lungs.

Corrective surgery is done in a series of three stages. The first stage, performed in the first days of life, is known as a Shunt Operation. During this procedure, a small tube (shunt) is placed between the aorta and the branch pulmonary artery. This helps increase blood flow to the lungs. The second and third stages are collectively known as the Fontan Procedure. The second procedure, performed at approximately six months of age, creates a Bi-directional Cavo Pulmonary Connection (BCPC).

This involves connecting the superior vena cava to the right pulmonary branch artery. The BCPC allows the deoxygenated blood of the upper half of the body to flow directly to the lungs. The shunt placed during the first stage operation is also ligated at this time. The third and final stage is performed at approximately 12 months of age. During this procedure, the deoxygenated blood of the lower half of the heart is directed to the lungs. This is done by channeling the blood of the inferior vena cava through the right atrium to the right branch pulmonary artery.

What Is Normal Cardiac Anatomy?

When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.

Heart With Normal Cardiac Anatomy

When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.

The heart is composed of four chambers. The two upper chambers, known as atria, collect blood as it flows back to the heart. The two lower chambers, known as ventricles, pump blood with each heartbeat to the two main arteries (the pulmonary artery and the aorta). The septum is the wall that divides the heart into right and left sides. The atrial septum separates the right and left atria; likewise, the ventricular septum separates the two ventricles.

There are four valves that control the flow of blood through the heart. These flap-like structures allow blood to flow in only one direction. The tricuspid and mitral valves, also known as the atrioventricular valves, separate the upper and lower chambers of the heart. The aortic and pulmonary valves, also known as the arterial valves, separate the ventricles from the main arteries. Oxygen-depleted blood returns from the body and drains into the right atrium via the superior and inferior vena cavas. The blood in the right atrium then passes through the tricuspid valve and enters the right ventricle.

Next, the blood passes through the pulmonary valve, enters the pulmonary artery, and travels to the lungs where it is replenished with oxygen. The oxygen-rich blood returns to the heart via the pulmonary veins, draining into the left atrium. The blood in the left atrium passes through the bicuspid, or mitral, valve and enters the left ventricle.

Finally, the oxygen-rich blood flows through the aortic valve into the aorta and out to the rest of the body.